Standard International Cartridge
Pens, Inks & Leads · 6 specs
Direct Answer
The Standard International Cartridge (also known as the European or Universal cartridge) is the dominant standardized fountain pen ink format, featuring a 2.4 mm nozzle opening sealed with a plastic sphere. Available in Short (38 mm / 0.85 ml) and Long (72 mm / 1.4 ml) sizes, it is used by dozens of European and American fountain pen manufacturers.
Source: DIN 16554 (Fountain pen ink cartridges) / European Stationery Conventions · Last reviewed Aug 28, 2026
Specs
| Short Cartridge Dimensions | 38.0 mm length × 7.0 mm diameter (approx. 0.80 to 0.85 ml ink capacity) |
| Long Cartridge Dimensions | 72.0 mm length × 7.0 mm diameter (approx. 1.40 to 1.50 ml ink capacity) |
| Bore / Nozzle Diameter | 2.4 ± 0.05 mm (friction-fits over the pen feed nipple) |
| Internal Seal | Floating polystyrene bead / puncture disc pushed into cartridge body upon insertion |
| Two-in-Barrel Tandem Storage | Most full-size pens store one active short cartridge plus one inverted spare short cartridge in the barrel |
| Brand Compatibility | Kaweco, Pelikan, Montblanc, Faber-Castell, Visconti, Diplomat, Caran d'Ache, Jinhao, Waterman (long) |
Universal European Interoperability
Unlike proprietary Japanese or American cartridges, the Standard International format allows fountain pen owners to use ink cartridges from any compatible maker. Compact pocket pens (such as the Kaweco Sport) accommodate only the Short 38 mm format, while full-length desk pens accept either one Long 72 mm cartridge or two Short cartridges held back-to-back.